Rotary pump



Sept. 24, 1935. w. l.. J. sPooR ROTARY PUMP Filed Jan. 6*,` 1932 Patented Sept. 24, 19,35

ROTARY PUMP willem mewuk Joost spoor, Amsterdam, rNetherlands Application January 6, 1932, Serial No. 5854172 In the Netherlands {anuary 12, 1931 The Vinvention relates to rotary impller pumps having an auxiliary sealing liquid and which are adapted i'or'pumping liquids as well as gases, so that they are always selfpriming.-`

5 In the usual pumps ofthis kind one or more guide passages for the auxiliary liquid are arranged laterally of the impeller, the said pas-- 4sage or passages having usually a rectangular cross section. For the sake of simplicity this l guide passage is referred to hereafter in the sin-v gular, but itis to be understood that thislterm includes also the case where more thanone' guide` passa'geis provided. The lift of known pumps of thiskind amounts to about 16 to 20 feet. With the use ofk a s pecial pump a lift or approximately 31 feet-can be obtained with an impeller having for example a diameter oi.' 150 mm, at 1450 revolutions per minute. I n the last named 'type ofypump the 20 liquid in the pump-is sometimes subjected to the vcentrifugal force more than once, consecutively. 'Ihus the liquid does not enter the impeller once and leave it once but goes through this cycle f several times,- which results inthe pressure reaching a multiple of the pressure got with single centrifugal action, the amount of which will bediscussed hereinafter. The invention-may be apl plied as well to pumps having such multiple centrifugal action. l l

3.0 "I'heinvention has ior its object the provision of an improved lift and operation oi' this class--V of pump whereby the usual guide `passage,\which is open to the impeller, is shaped ina special way. f

The usual openl guide passages have a cross section which is substantiallyrectangular or of quadratic shape. It has now been shown that this shape is not advantageous and cannot leadto the best results. 'v According to the invention this disadvantage is overcomeby imparting a special shape to the guide passage. yThe fundamental idea of the in-v vention consists in giving to the guide passage a rounded cross section. i

It is known thatfthe auxiliary liquidfollows a helical path in the guide passages and the fundamental thought of the invention consists in so shaping the guide passage that little, or the smallest possible, resistance in the guide passage is offered to this helical movement. In the first place, therefore, dead corners or spaces in the. passage are avoided by giving the passage va rounded cross section. These dead corners cause eddies which greatly influence the movement of L the auxiliary liquid in the passage,

- passage and thevl spaces Good results are obtained by giving to the guide passage a semi-circular cross section. `A still better result is obtained if the guide passage has a triangular cross section, in such a way that the passage is widest at the extreme periphery 5 of the impeller. `Of course' in thelatter case the apex ofthe triangle can berounded. Further, the effectiveness oi.' the pump can be still further increased by gradually decreasing the cross section oi the guide'passage from the in- 10 let to the outlet.` The eiect obtained can be still further increased by arranging the guide passage insuch a way that the centre line of the guide passage is gradually displaced from the centre of the pump, in the direction from the 15 inlet towards the outlet of the pump.-

A step which is also favourable to the operation of a pump of the kind referred to is the arrangement of a core which is' arranged in the longitudinal. direction of the passage, and is connected merely by` supporting arms'with the walls oi the guide passage. 1

Finally, guide vanes can be arranged in the guide passage, the screw pitch oi.' the said vanes decreasing from the inlet to the outlet.

Experiments have shown'` that by the steps above mentioned, either individually or indeilnite combinations, the efliciency oi the pump and j especially its lift are greater than has hitherto `been obtainable, and that the capacity of a pump power three times that of the motors which have hitherto been used, can be used now. The reasony for obtaining the increased lift and better eciency of the pump according to the invention is to be attributed to the helioallke movement of the auxiliary liquid through the guide between the vanes of the impeller. 40

In a pump according to the invention the smallest possible resistance is oiered to the helical- 2 like movement of the auxiliary liquid by various steps which, however, all relate to the shape of the guide passage. The consequence of this is that the pitch of the liquid'during its helical movement is a1- Ways decreasing the nearer the liquid approaches the outlet. The diminution-in the pitch, however, brings about an increase in the speed of the movement of rotation of the liquid. This e movement'of. rotation is completed therefore in the neighborhood of the outlet of the pump in planes which approximately coincide with planes passing through the axis of the pump.

This mass of water revolving with great speed produces, in consequence oi' a gyroscopic action,

resistance to any adjustment in a direction perpendicular to the direction of revolution. This explains the reason why the mass of auxiliary liquid cannot be pressed back into the guide passage by a column of water of great height, and why the lift of this pump is extremely high.

' Several forms of the invention are illustrated by way of example in the drawing, wherein:

Fig. l is a vertical section through a pump of known construction;

Fig. 2 is a side view of the inside of the right half of the pump casingwith the guide passage according to Fig. 1;

Fig. 3 is a cross section through a part of a pump according to the invention, in which the guide passage has a rounded form in cross section; l

i Fig. 4 is a cross section as in Fig. 3, in which. however, the guide passage has a semicircular cross section;

Fig. 5 is a similar cross section to Fig. 4, but wherein the guide passage has a triangular cross section;

Fig. 6 is a view similar to Fig. 2. namelyy an inside view of the half of a pump casing in which the guide passage is arranged;

Fig. 'I is an axial cross section of a pump similar to that of Fig. 6 but having guide passages at both sides of the impeller which is a common construction in this kind of pump;

Fig. 8 is a view similar to Fig. 6. but having a core arranged in the guide passage and provided with guide vanes, the pitch of which, decreases from the inlet to the outlet;

Fig. 9 is a diagram comparing curves of thelift and output oi known pumps and of a pump according to the invention.

'I'he cross section illustrated in Fig. 1 is` the cross section ot a known type pump with a single guide passage. These pumps `are often made with two guide passages, in which case the second guide passage is arranged in the other half; (in the left half in the drawing) of the pumpcasing.

The shaft of the impeller is indicated by I, and the impeller by 2, whilst the right half of the pump casing is indicated by 3.4 The guide passage lot. the known pump has a rectangular cross section having sometimes corners which `are slightly rounded.

In Fig. 2 the outlet is indicated by 5. The inlet is not arranged in this half of the pump casing but is disposed in the left half of the pump casing, opposite tothe opening marked 6. Fig. 2 shows the pump turned 90 in a clockwise. direction relatively to the actual position of the pump. The openings 5 and 6 thus are disposed one above the other in one vertical line, while they are disposed in practice on a horizontal line. It is done in order to have the possibility that in vertical cross sections of Fig. 2 (such asv Fig. 1) the guide passage is traversed two times, so that cross sections of the same guide passage in two points of its length can be illustrated.

Fig. 3 illustrates a cross section of the guide passage 41 according to the invention, that is with a rounded shape.

In Fig. 1 the dotted circle 1 indicates the projection of the helical path followed by the liquid on its way through the guide passage, and through the intermediate spaces between the vanes of the impeller.

In the known pump (Fig. l) a relatively large dead spaceis left around the dotted circle in the aoiaaoo guide passage. In this dead space eddies are formed which have a great influence on the helical movement of the liquid. In the constructional form of the guide passage according to Fig. 3, in which the cross section of the guide passage has a rounded shape, the dead space has largely disappeared.

A pump. with a guide passage according to Fig. 3 is a considerable improvement on`known pumps. The circle 'I1 in Fig. 3 shows that the dead space has approximately disappeared.

Fig. 4. illustrates how according to the inven` tion the cross section oi the guide passage is formed as an arc l11' a circle. The circle I showsthat the dead space has quite disappeared, that is ii it is assumed that the projection of the helical path followed by the mass of water is a circle. It appears, however, that in case the guide passage Is given a triangular shape, as illustrated in Fig. 5, the effectiveness of the pump is still further increased. The projection of the said helical path appears therefore to be approximately elliptical.

A further feature of the invention is obvious from Fig. 6, which illustrates an inside view of one half of the pump casing. The guide passage 4* decreases in cross section, calculated from the inlet to the outlet 5 and varies in shape. In order to indicate this in the drawing, planes 8 9, 8-I'0 and l-II extending out from the central axis of the pump are indicated by dotted lines. `These planes intersect the guide passage at different points indicated at I2, I3 and Il, at which the cross sectional shape of the passage is diagrammatically shown. The area of the cross sections I2, I3 .and I4 gradually decreases and the shape of the passage varies. In this figure the centre of rotation of the liquid is illustrated by the dotted line I5 which is also to be found in the cross sections I2.' I3 and Il.

vIn a constructional form ofthe invention this centre line is gradually removed from the central axis I of the pump from the inlet to the outlet of the pump.

Fig. 7 illustrates how pumps according to the invention may have guide passages at both sides of the impeller. In'such a manner the pump action as to the output of the pump is doubled. The line I5 illustrating the center oi' rotation is indicated also in Fig. 7 for each guide passage. It does not need to coincide exactly with the geometrical center of the half circle of the cross section of the guide passage, because the center of rotation of the liquid in the guide passage has a tendency due to centrifugal action to creep to the periphery of the impeller. vThe said centerv of rotation of the liquid may be marked or xed by a core materializing as it were the said center.

Such a corey may be arranged as illustrated in Fig. 8. This core I6 traverses the 'whole guide passage and can be connected through supportis made to Fig. 9 of the drawing. Line O-V indicates the output in litres per minute, and line O-H indicates the manometric lift H in metres of the water column. The curves were obtained from pumps having an impeller of 150 mm. centre line diameter, and a speed of rotation of 1450 revolutions per minute. The curve .A applies for a normal known centrifugal or water ring pump. The curve B is obtained from the best pump of this kind, for example the Sihi pump, and the curve C is obtained from a pump according to the invention. It may be remarked that newer pumps according to the invention have reached already still higher values than indicated by the curve C. The top of this curve then reaches line O--H not before the point 69, according to a manometric lift oi 69 metres of the water column.

The pumps according to the invention are naturally not limited to single-acting pumps as shown in the drawing, but the invention extends also to double-acting pumps, in which, therefore, the guide passage is arranged at both sides of the impeller.

What I claim is:-

1. Rotary pump comprising an impeller lined at the periphery with vanes and a casing enclosing the said impeller with a substantially liquid tight running iit and having open guide passages arranged laterally of the impeller, said guide passages extending opposite the vanes of the impeller for the greater part of a circle but having two dead ends, inlet and outlet openings being provided laterally of the impeller in the casing and lying radially inward of the guide passages and Within the reach of the annular area occupied by the vanes on the-side face of 5 the impeller, the height of the said vanes calculated in a radial direction being greater than the width of the guide passages in the casing also calculated in a radial section, the radial cross sections of the guide passages being shaped in conformity with the movement of the liquid taken in a radial plane, said passages being triangular in shape adjacent the inlet and having the greatest depth near the outer periphery ot the impeller and gradually changing to a semicircular shape adjacent the outlet, the bottom of the passage being rounded even throughout the triangular portion.

2. A rotary pump as claimed in claim 1 characterized b'yithe provision of a core arranged in 20 the guide passages and in the longitudinal direction thereof, said core lying adjacent the vanes of the impeller and containixm the center of rotation of the whirling liquid. A

3. A rotary pump as claimed in claim l characterized by the `provision of vanes arranged in the guide passages adapted to guide the liquid in a helical path, the pitch of the vanes decreasing from the inlet opening to the outlet opening.

WILLEM LODEWIJK JOOST SPOOR.. 

